In general, an LCD device includes a liquid crystal display panel consisting of a thin film transistor (TFT) substrate and a color filter substrate which are attached with a certain interval therebetween so as to face each other and a liquid crystal layer provided between the TFT and color filter substrates, a driving unit for driving the liquid crystal display panel, and a backlight unit for supplying light to the liquid crystal display panel.
The TFT array substrate includes a plurality of data lines vertically arranged with a certain interval therebetween, a plurality of gate lines horizontally arranged with a certain interval therebetween, and a pixel defined at each crossing of the data line and the gate line and formed in a matrix form.
The color filter substrate includes a red, green and blue color filter layer formed at positions corresponding to the pixels and a black matrix for preventing leakage of light between the color filters and color interference of light passing through the pixels.
A common electrode and a pixel electrode face inner surfaces of the color filter substrate and the TFT array substrate, respectively, and apply an electric field to the liquid crystal layer. In this case, the pixel electrode is formed on the TFT array substrate according to each pixel and the common electrode is integrally formed on the entire surface of the color filter substrate. Accordingly, by changing an arrangement state of liquid crystal molecules of the liquid crystal layer by controlling a voltage applied to the pixel electrode in a state that a voltage is applied to the common electrode, light transmittance of pixels can be individually controlled.
The backlight unit supplies light to the LCD device, which cannot emit light by itself. When light emitted from the backlight unit passes through the liquid crystal layer, light transmittance is determined according to the arrangement state of liquid crystals, and accordingly, an image is displayed.
FIG. 1 is an exploded perspective view showing a general LCD module.
As shown, the LCD device includes a liquid crystal display panel 10 having pixels arranged in a matrix form; a gate driving unit 20 and a data driving unit 30 connected at the sides of the liquid crystal display panel 10; and a backlight unit 40 disposed on a rear surface of the liquid crystal display panel 10.
The liquid crystal display panel 10 includes a TFT array substrate and a color substrate attached so as to face each other with a uniform cell gap maintained therebetween, and a liquid crystal layer formed at the isolated space between the color filter substrate and the TFT array substrate.
A common electrode and a pixel electrode are formed on the liquid crystal display panel formed as the TFT array substrate and the color filter substrate are attached, and apply an electric field to the liquid crystal layer.
When a voltage of a data signal applied to the pixel electrode is controlled in a state that a voltage is applied to the common electrode, liquid crystals of the liquid crystal layer rotate due to dielectric anisotropy according to the electric field between the common electrode and the pixel electrode to transmit or shield light for each pixel to thereby display a character or an image. In order to control a voltage of the data signal applied to the pixel electrode, a switching device such as a TFT is provided at each pixel.
The gate driving unit 20 and the data driving unit 30 are coupled with the liquid crystal display panel 10 in various ways to supply a scan signal and image information to the gate lines and data lines formed on the liquid crystal display panel 10 to drive the pixels of the liquid crystal display panel 10.
The backlight unit 40 includes a light guide plate 41 disposed on a lower surface of the liquid crystal display panel 10, a lamp 42 and a lamp housing 43 disposed at both sides of the light guide plate 41, and a reflection plate 44 disposed on a lower surface of the light guide plate 41. An optical sheet 45 is disposed between the liquid crystal display panel 10 and the light guide plate 41.
As mentioned above, the liquid crystal display panel 10 and the backlight unit 40 are mounted on a main support 50 and an upper edge of the liquid crystal display panel 10 is pressed by a top case 51. The top case 51 is coupled with the main support 50 and a lower cover 22 disposed on the rear surface of the backlight unit 40.
An inverter (not shown) for supplying a drive voltage to the lamp 42 is separately provided to drive the backlight unit 40. The inverter can be provided at one side of the lamp 42 or at both sides of the lamp 42. If the inverter is provided at both sides of the lamp 42, a high voltage is applied to one inverter and a low voltage is applied to the other inverter. The inverters are protected by a metal cover 58 provided at a lower surface of the lower cover 52. The inverters provided at both sides of the lamp are connected by the FFC by circuitry, and the FCC connects both inverters after passing through the lower surface of the lower cover 52.
FIG. 2 illustrates the lower surface of the lower cover. As shown, metal covers 58a and 58b for protecting the inverters are provided at both sides of the lower cover 52, and the FFC 55 connecting the inverter connects a master portion applying a high voltage to one side of the lamp by traversing the lower cover 52 and a slave portion applying a low voltage to the other side of the lamp. In order to fix the FFC 55 to the lower cover 52, a piece of tape 60 is attached on the regions where the FFC 55 passes through. In this case, if the tape 60 is attached on the entire region where the FFC 55 passes through, operability is degraded, so the tape 60 is partially attached at certain intervals. However, portions of the FFC that do not have the tape 60 may become separated (i.e., get loose or bulge away) from the lower cover 52, and since the FFC 55 is exposed, it can be easily damaged.